Process of obtaining ortho and para nitro benzaldehyde.



UNITED STATES PATENT OFFICE.

BENITO HOMOLKA, OF FRANKFORT-ON-THE-MAIN, AND AUGUST STOCK, OF

HOOHST-ON-THE-MAIN, GERMANY, ASSIGNORS TO THE FARBWERKE, VOR- MALS MEISTER, LUOIUS & BRUNING, OF llOOHST-ON-THE-MAIN, GERMANY.

PROCESS OF OBTAINING-ORTHO AND PARA NITRO BENZALDEHYDE.

SPECIFICATION forming part of Letters Patent No. 636,994, dated November 14:, 1899.

Application filed December 15, 1897.

facture of Ortho-Nitrobenzaldehyd and Para- 1o Nitrobenzaldehyd, (for which we have obtained Letters Patentin Germany,No. 93,539, dated February 21, 1897, and No. 97,948,dated September 3, 1897; in France, No. 273,423, dated December 22, 1897, and in England, No.

I5 30,118, dated December 20, 1397,) of which the following is a description.

This invention relates to the production of ortho-nitrobenzaldehyd and para-nitrobenzaldehyd.

The nitrobenzylidenanilinsulfonic acids of the general formula:

where R represents the aromatic radical of 25 benzene, 0 H, of toluene, 0,11 of Xylene,

acids they decompose at once in presence of' water into nitrobenzaldehyd and anilinsulfonic acid (or a homologue of the same) ac- 5 cording to the following equation:

Ortho-nitrobenzylidenanilinsulfonic acid.

0 H, +H,N. c n, sc n (2 No Orthomitrobenzaldehyd. Anilinsulfonic acid.

(1)OH::N.O H SO l-I (16H4 H2O (4)N02 Para-nitrobenzyliden-toluidinsulfonic acid.

1 con 5 c n +H,N.o,H,.so,H

I aranit-robenzaldehyd. Toluidinsulfonic acid.

Serial No. 662,030. (No specimens.)

This behavior of the aromatic nitrobenzyli densulfonic acids offers a simple means for the manufacture of orthoand para-nitrobenzaldehyd.

To illustrate the practical application of our process, we proceed, for instance, as follows: 7

Manufacture of para m'trobenzaldeh'yd from para nitrobenzyhdcnanil'msubbnic acids.'lhirty-three kilograms para-nitrobenzylidensulfonate of sodium or the equivalent quantities of para-nitrobenzyliden-toluidinsulfonate of sodium, para-nitrobenzyliden-Xylidinsulfonate of sodium,or para-nitrobenzyliden naphthylaminsulfonate of sodium are dissolved in about fifteen hundred liters of warm water, whereupon a quantity of dilute mineral acid (HOl SO H &c.) equivalent to the quantity of present sodium salt is added. By these means para-nitrobenzylidenanilinsulfonic acid is set free and decomposes at once, according to the equations mentioned above, into para-nitrobenzaldehyd and anilinsulfonic acid or toluidinor Xylidinsulfonic acids. The para-nitrobenzaldehyd is soluble with difficulty in water, therefore separates, is filtered, and dried. In the filtrate remains dissolved the anilinsulfonic acid, toluidinor xylidinsulfonic acid. In the same way orthonitrobenzaldehyd is obtained if instead of the above-mentioned para-nitrobenzylidenanilintoluidin-.Xylidinor naphthylaminsulfonic acids the ortho-nitrobenzyliden-anilin, toluidin, xylidin,or naphthylaminsulfonic acids be used and less water employed. As, however, ortho-nitrobenzaldehyd is far more soluble in water than para-nitrobenzaldehyd, it does not separate so completely as the latter. It is therefore necessary to obtain the residual ortho-nitrobenzaldehyd either by extraction with ether or benzene (toluene, Xylene, &c.) or by distilling ed with steam. This circumstance renders the process far more difficult and costly, and we consequently endeavored to find a better process for the manufacture of ortho-nitrobenzaldehyd. We succeeded in finding such a process by making use of a second peculiar chemical reaction which is characteristic for the orthoand para-nitrobenzyliden-anilin (toluidinand Xylidin-) sulfonic acids. If, for instance, upon the aqueous solution of a salt of an orthoor para-ninaphthylamin) sulfonic acid; second, the orthoor para-nitrobenzyliden compound of' anilin, (toluidin, xylidin, naphthylamin,) and, third, chlorid of sodium (oran other inorganic alkalin salt) according, for instance, to the following equations:

(1) onzv. o in- SO Na 1. 0 H +C H .NH .HCl=

2)No Ortho-nitrobenzylidenanilinsulfonatc of Hydrochloride of sodium. anilin.

(1) OHzN. o r-1 C 11 +H N. o n SO H+NaCl 2 Ortho-nitrobenzyliden- Anilinsulfonic acid.

anilin. (1) oII=N.o,I-I,- SO Na (1)CH=N. 0,11 2. c n, o,H,.NH,.Ho1= 0 H (4)NO (4)NO +H N.C H SO II+NaCL Para-nitrobenzyliden-toluidin- Hydrochloride of P-nitrobenzyliden- Toluidinsulfonic acid.

sulfonate of sodium. toluidin. toluidin.

Of the products of reaction thus obtained the anilin- (toluidin Xylidin-) sulfonic acid and the chlorid of sodium are soluble in water. The orthoor para-nitrobenzyliden base, however, is completely insoluble in water, therefore separates and may be decomposed after filtering off in the usual way with diluted mineral acids into orthoor para-nitrobenzaldehyd and the anilin base according to the equation: NO G l-I OH: N. C H +H O Paraor ortho=nitrobenzylidenanilin.

N0 .(J H COH-PH N.O H Paraor ortho-nitro- Anilin.

benzaldehyd.

For the production of ortho-nitrobenzaldehyd we proceed, for instance, as follows: Thirty-three kilograms of ortho-nitrobenzylidenanilinsulfonate of sodium or the equivalentquantity of a salt of ortho-nitrobenzylidentoluidin, xylidin, or naphthylamin -sulfonic acid are dissolved in about one thousand to fifteen hundred liters of water, to which is added,with stirring, a solution of 14.5 kilograms hydrochloride of toluidin (or the equivalent quantity of another toluidin salt or of an anilinor Xylidinor naphthylamin salt.) The reaction takes place as above described, when the entire ortho-nitrobenzaldehyd separates in form of ortho-nitrobenzyli den-toluidin. The latter is separated from the liquid and decomposed in the usual Way with diluted mineral acids into ortho-nitrobenzaldehyd and toluidin. In the same way para-nitrobenzaldehyd is obtained from paranitrobenzylidenanilintoludinxylidinor naphthylamin-sulfonic acids.

Having now described our invention, what we claim is The herein-described process of producing orthoand para-nitrobenzaldehyd, which consists in bringing nitrobenzylidenanilinsulfm nates, where the nitro group is in ortho or para position to the CH group, into reaction with the salts of a primary aromatic base, and then treating the nitrobenzyliden bases thus obtained in the usual manner with diluted mineral acids, substantially as set forth.

In testimony that we claim the foregoing as our invention we have signed our names in presence of two subscribing witnesses.

BENNO HOMOLKA. 'AUGUST STOCK. Witnesses:

HEINRICH HAHN, ALFRED BRIsBIN. 

